configuring serial interfaces

totts

Hope someone can help!!

I recently bought a couple of 2500 routers from e-bay for training on and they seem to be working fine (in fact I had to do password recovery on one which went ok). My problem is that I can't bring the serial interfaces up.

I've configured s0 as...

204.204.7.1 255.255.255.0

and carried out a 'no shut' but I can't budge them from 'down down'

Has anyone got any suggestions.
Many thanks.

malcybood

have you connected the serial interfaces together with a db60 crossover cable and they are still down?

markzab

To add to malcy, do you have the DCE side of that cable (if in fact you do have cables connecting 2 routers) set with a clock rate?

totts

malcybood wrote:

have you connected the serial interfaces together with a db60 crossover cable and they are still down?

Thanks for your reply malcybood, I didn't connect them. I thought you could bring the serial interfaces 'up up' without doing so. I worked on a lab several years ago and only seem to remember using one router (so therefore not connecting any interfaces). I'll configer the interfaces to an appropriate addressing scheme and set the clocking on the DCE end and see how I get on. Cheers!

markzab

Good luck.

malcybood

totts wrote:

malcybood wrote:

have you connected the serial interfaces together with a db60 crossover cable and they are still down?

Thanks for your reply malcybood, I didn't connect them. I thought you could bring the serial interfaces 'up up' without doing so. I worked on a lab several years ago and only seem to remember using one router (so therefore not connecting any interfaces). I'll configer the interfaces to an appropriate addressing scheme and set the clocking on the DCE end and see how I get on. Cheers!

No worries mate, whilst i was studying for my CCNA back in the day I remember I had 3 routers each with a Fast Ethernet port and couldn't work out why I couldn't ping one of them as I had done the night before.

It turned out I had the switch connected to that interface powered down meaning I couldn't ping it. I plugged the magic kettle lead into the switch and voila got a reply from the ping.

If you try the above and still can't get it to work come back to us.

cheers
malc

totts

markzab wrote:

To add to malcy, do you have the DCE side of that cable (if in fact you do have cables connecting 2 routers) set with a clock rate?

Cheers markzab, connecting everything up now. As per my reply to malcy, I didn't connect the two routers up in the belief that they didn't need it!

totts

malcybood wrote:

totts wrote:

malcybood wrote:

have you connected the serial interfaces together with a db60 crossover cable and they are still down?

Thanks for your reply malcybood, I didn't connect them. I thought you could bring the serial interfaces 'up up' without doing so. I worked on a lab several years ago and only seem to remember using one router (so therefore not connecting any interfaces). I'll configer the interfaces to an appropriate addressing scheme and set the clocking on the DCE end and see how I get on. Cheers!

No worries mate, whilst i was studying for my CCNA back in the day I remember I had 3 routers each with a Fast Ethernet port and couldn't work out why I couldn't ping one of them as I had done the night before.

It turned out I had the switch connected to that interface powered down meaning I couldn't ping it. I plugged the magic kettle lead into the switch and voila got a reply from the ping.

If you try the above and still can't get it to work come back to us.

cheers
malc

nice one! These are the best lessons, thats why I invested in the routers rather than the soft option of some training software. Thanks again.

totts

markzab wrote:

Good luck.

All done... works a treat! thanks for your help.

Webmaster

Additionally, you may want to check out our Configuring a RIP network TechLab. Despite it's title, it covers the basics of setting up the serial link to:
www.techexams.net/techlabs/ccna/lab_1_rip.shtml
(ppp encapsulation is optional because HDLC is used by default)

totts

totts wrote:

Hope someone can help!!

I recently bought a couple of 2500 routers from e-bay for training on and they seem to be working fine (in fact I had to do password recovery on one which went ok). My problem is that I can't bring the serial interfaces up.

I've configured s0 as...

204.204.7.1 255.255.255.0

and carried out a 'no shut' but I can't budge them from 'down down'

Has anyone got any suggestions.
Many thanks.

Got the serial interface up... but of course it ends up posing more questions, I can put any ip address in (ie totally different subnet and class come to that) and it remains 'up up'... some kit eh!

Paul Boz

No that's right. The interfaces can be up/up without matching IP addresses. Being able to troubleshoot mismatched address schemes is actually a pretty important skill you should take away from the CCNA.

SneakerNet

Really goes a long way to show everyone that having the gear on hand makes a huge difference. I could share some stories with you about some of the things I did when my first routers showed up.

We have all been there. Learned alot trying to fix it and I am sure I will do it again.

Congrats on working through your problem and asking for help when you needed it.

Darthn3ss

to keep the serial interface up like you had said i belive you need to use no keepalive for that....